The "catastrophic" hot weather caused a 10km stretch of the Hume Highway, near the Victoria state capital Melbourne, to become soft and sticky, causing havoc for motorists trying to enter the city.
Victoria, South Australia and Tasmania have now declared a total fire ban after blazes on the outskirts of Melbourne raged out of control, destroying buildings and threatening lives.
It took a team of 300 firefighters, 50 trucks and three helicopters to tackle one fire in Victoria's Carrum Downs on Saturday, which threatened dozens of homes.
And another 49 bushfires are said to have been reported across the state - although many were small and easily extinguished - with 400 residencies losing power.
The state's emergency management commissioner, Craig Lapsley, said hot temperatures had combined with dry weather, strong winds and a wind change to create dangerous conditions.
"It's exactly what the forecast indicated and when we have fires running that's obviously a problem for us," he said.
Temperatures are expected to exceed 40°C in the southeast, with the country's Bureau of Meteorology forecasting highs of 45°C in Penrith, 44°C in Richmond and 43°C in Liverpool, with much of the area being rated as 'catastrophic' or 'code red' by emergency services.
Australia is prone to deadly blazes thanks to its combination of remote terrain, high summer temperatures and flammable eucalyptus bush.
In 2009, the worst bushfires on record destroyed thousands of homes in Victoria, killing 173 people and injuring 414 on a day the media dubbed "Black Saturday".
Australia's winter in 2017 - which runs from June to August - was the hottest ever recorded with the Bureau of Meteorology attributing it to a "long-term warming trend" mostly caused by climate change.
The South Australian County Fire Servce (CFS) issued an emergency warning for Sherwood, Brimbago, Lowan Vale, McCallum and Senior areas near the Victorian-South Australian border.
"If you are in this area you are in danger," a statement said. "There is a risk to your life and property.
"Take shelter inside a solid building. Do not leave or enter this area in a vehicle or on foot. It is too late to leave and the roads will not be safe."
NSW Health also released a statement saying emergency services were ready to respond to possible fatalities as a result of the weather.
"A NSW Health study published last month found extreme heatwaves lead to a more than ten percent increase in both deaths and ambulance callouts," said Dr Ben Scalley, director of environmental health at NSW Health.
"They put a lot of strain on the body and can cause dehydration, heat exhaustion and heat stroke."
And speaking to reporters, Ambulance Victoria's state health commander issued a warning for the state's residence to take the heat "seriously".
"This heat is a killer. It's going to be like a blast furnace tomorrow and you need to adjust what you do," he said.
In August 2017, bushfire conditions in the east of the country reached "near record levels" following what was believed to be the driest winter since 2002.
At the time, Andrew Watkins of the Bureau of Meteorology said: "We've certainly seen a shortening of our winters."
Reader Comments
About a mile away there was a little German cemetery. It took up maybe half an acre, and had been there, under the scorching Queensland sun, since the first grave was dug in 1914 for Edward Schloss, aged 22. The last grave was filled by Adolph Schloss (aged 59) in 1955. There are only seven names recurring on all the gravestones – Baum, Leisch, Kleidon, Schrek, Schroder, Shultz, and Schloss. None of those names exist in the locality any more. There are twenty five graves and twelve are those of children aged from 8 days to eleven years. Only three people in the graveyard lived to reach 65 years of age.
Australia is a hard country but the Aussies are used to it and I was most impressed by the way they love and look after the distinctive flora and fauna of their country.
I stop breathing in the heat, signed: zee penguin
I recall as a 12 year old we'd wait for such weather, then go down the streets scraping off the melted tar, collecting it in a Sunshine milk powder tin to take home to seal the holes in our corrogated iron canoe we built, then taker them down to the local dams were we swam and mucked about in the muddy water all day long. Hot weather ? We loved it. Still do to this day.
It's far easier and cheaper to stay cool in hot weather than it is to stay warm in freezing below temps.